Production of patterns on cloth or similar substances



1963 K. A. METCALFE ETAL 3,102,045

PRODUCTION OF PATTERNS ON CLOTH OR SIMILAR SUBSTANCES Filed June 25,1958 United States Patent This invention relates totheproductionofpatterns on cloth or similar substances such ascanvas or the like.

Printing of patterns on cloth is usually effected by either runningthecloth beneath printing rollers inked in any normal manner orbyweaving in threads which have been pre-printed and which rwillthengive therequired pattern when woven.

The present invention relates to the production of patterns on cloth orthe like which has already been proposed, but instead of printingbymeans of dyes in the normal manner, the pattern is, according to ourinvention, produced on the cloth by electrostatic printing.

' The method of producing the printed patterns according to thisinvention comprises applying an electrostatic pattern by means of'aphotoconductor surface to a cloth or similar substance and applyingliquid developer to the cloth or similar substances as it is incontactwiththe electrostatic pattern, whereby the developer which forms thecoloring medium will be deposited 'on; the cloth in accordance with theelectrostatic pattern on the control member. Y 7

The device for producing the printed patterns on the cloth or similarsubstances comprises a control member having a photo-conductor surfaceon it and means to press the cloth into contact with the saidphotoconductor surface, and means to apply developer at the area ofcontact.

To enable the invention to be fully understood embodiments thereof willnow be described with reference to the accompanying drawings in which:

FIG. 1 shows schematically how the pattern can be applied by using acontrol member which has the electrostatic pattern thereon, the controlmember with the cloth thereon being submerged beneath the developer,

FIG. 2 shows how the developer may be applied to the cloth by a rollercarrying the'developer, and

FIG. 3 shows acontinuous process in which a control member having aphoto-conductor surface controls the pattern on the cloth as the clothpasses over a developer roller.

Referring first to FIG. 1, a developer dish 1 has in it the developersolution 2 which consists of a pigment or dye which is to form thecoloring medium for the cloth or the like suspended in a liquid of highelectrical resistivity. Into this dish is placed a control member 3which may comprise a plate or the like having a photo-conductor surface4 on it such as a zinc oxide set in a suitable bonding resin. Thephoto-conductor surface 4 has a pattern on it which can be produced inany conventional manner such as by charging the photo-conductor materialand then bleeding away the charge by projecting a light pattern onto thesurface, the cloth 5 being placed on the photoconductor surface 4 of thecontrol member 3 prior to submerging of the control member into thedeveloper solution. Alternatively, the developer 2 can be poured intothe dish 1 after the control member 3 and the cloth 5 have I beenlocated in the dish.

It is normally desirable to contact the cloth with the developer onlywhen it is in contact with the control member as this insures that thedye or pigment of the developer 2 is deposited only in predeterminedareas,

the charge on the control member being so selected 3,102,045 PatentedAug. 27, 1963 ice that there is the necessary gradient which will insurethat the pigment particles or the dye will flow as indicated, forexample, by the arrows 6 in FIG. 1. Those areas where no deposition isto take place will be denuded of the pigment or dye by the dew whichtakes place to the charge areas 7'which attract the dyeor pigment tosuch areas.

Instead. of using a negative developer a positive developer could beused, in which case the movement of the particles or dye will be in adirection opposite to that shown in FIG. 1. l

It will be obvious that a negative charge could be used on the controlmember, such as by using zinc oxide, although a-positive is shown in theillustration.

The developer will of course have such a proportion of carrier liquid topigment that discoloration of the cloth will not take placeundersirably.

An example of a positively charged developer paste is as follows:

Grams Pentar-ol 20" l5 Rhodene L6/ 100 15 Xylene 25 Phthalocyauine blue'l5() The Pentarol 20 is digested in xylene and when solution iscomplete the Rhodene L6/ 100 is added. The phthalocyanine blue is thenrnixed with the resins and blended either in a ball mill or triple rollmill until mixing is complete and pigment particle size isreduced to therequired fineness, such as 0.5 micro, average. For most purposes eighthours milling in a ball mill should be found suflicient. An example of anegatively charged developer paste is as follows:

Grams Boiled linseed oil 25 Lead chromatecn' Drier, lead n aphthenate0.5

The ingredients are milled together for eight hours in a ball mill.

Inboth cases, the paste is used as the basis for a dispersion in aliquid of high volume resistivity. An example of the method ofdispersion is as follows: stir a small portion of the paste into therequired liquid, such as n-pentane or carbon tetrachloride, and strainto remove portions :of paste that have not completely dispersed. Forfine grained developers filter before use through filter paper and usefiltrate as a developer. The concentration of the dispersion may bevaried at will, a typical concentration of 'a preferred dispersion beinga suspension of 0.5 gram developer paste in mil of liquid.

In the embodiment shown in FIG. 2 the cloth 5 is shown in position onthe control member 3 but the developer is being applied by means of aroller 8 having an absorbent cover 9 which carries the developer, theprinci ple of operation being the same as with reference to FIG. 1 inthat as the roller carries the developer over the cloth 5, the developeris accepted at the areas 7 but is rejected at the other areas due to thefact that the developer particles or the dye have an inherent chargewhich can cause deposition only at the areas on the cloth where thecontrol member gives the opposite polarity.

FIG. 3 shows a system somewhat similar to that of FIG. 2 but of acontinuous type.-

In FIG. 3 the dish 1 has in it the developer 2 and mounted to dip intothe developer 2 is a roller 8 having a surface 9 which is \wetted by thedeveloper, the rollers being free to revolve about its spindle 10.

The cloth 5' is fed over this roller and is in contact with the surfacewhich is wet with developer, but in this case the control member 3consists of a roller '11 having a photo-conductor 12 on its surface, theroller contacting the cloth at the point of its contact with thedeveloper roller.

The control member 3 has its charge pattern regulated by a drum 13 whichrevolves around a shield 14 having a slit 15 in it adjacent a lightsource 16 so that as the drum 13 which carries the negative or otherpattern-producing member is revolved, the pattern is projected by thelight source 116 through the slit 15 onto thephoto-conductor face of theroller 11 to modify the charge pattern on it, a corona discharge device17 being of course used to charge the photo-conductor surface prior tothe charges being modified by the light beam from the source 16.

In this way as the cloth passes around the photoconductor surface 12 onthe control member 3', the image -is developed by contact with thesurface 9 of the developer roller 8.

By this invention, direct pattern deposition on to cloth can thus takeplace without the cloth itself having to be provided with aphoto-conductor surface.

In the claims the expression cloth is to be understood as includingsimilar substances. 5

What is claimed is:

1. The method of producing printed patterns on cloth comprising applyingan electrostatic pattern to a photo conductor surface on a controlmember, placing one side of the cloth on to the control member so thatthe electrostatic pattern extends through the cloth, applying liquiddeveloper directly to the other side of the cloth as it is subjected tothe electrostatic pattern of the control member, and subsequentlyremoving the cloth from the control member.

2. The method of producing printed patterns on cloth comprising applyingan electrostatic pattern to a photo conductor surface on a controlmember, placing one side of the cloth on to the control member so thatthe electrostatic pattern extends through the cloth, applying liquiddeveloper directly to the other side of the cloth by rolling it on asthe cloth is subjected to the electrostatic pattern of the controlmember, and subsequently removing the cloth from the control member.

3. The method of producing printed patterns on cloth comprising applyingan elastrostatic pattern to a photo conductor surface on a control drum,and feeding a web of cloth between the said drum and a developer rollercarrying a liquid developer so that one side of the cloth is in contactwith the control drum and the electrostatic pattern extends through thecloth, and whereby the liquid developer is applied directly to the otherside of the cloth as it is subjected to the electrostatic pattern of thecontrol drum.

References Cited in the file of this patent UNITED STATES PATENTS1,818,760 Selenyi Aug. 11, 1931 2,053,494 Pirie et al. Sept. 8, 19362,143,376 Hansell Jan. 10, 1939 2,297,691 Carlson Oct. 6, 1942 2,520,504Hooper Aug. 29, 1950 2,633,796 Pethick Apr. 7, 1953 2,693,416Butterfield Nov. 2, 1954 2,811,465 Grieg Oct. 29, 1957 2,869,461 JarvisJan. 20, 1959 2,877,133 Mayer t Mar. 10, 1959 2,898,279 Metcalfe Aug. 4,1959 FOREIGN PATENTS 755,486

Great Britain Aug. 22, 1956

1. THE METHOD OF PRODUCING PRINTED PATTERNS ON CLOTH COMPRISING APPLYINGAN ELECTROSTATIC PATTERN TO A PHOTO CONDUCTOR SURFACE ON A CONTROLMEMBER, PLACING ONE SIDE OF THE CLOTH ON THE CONTROL MEMBER SO THAT THEELECTROSTATIC PATTERN EXTENDS THROUGH THE CLOTH, APPLYING LIQUIDDEVELOPERDIRECTLY TO THE OTHER PATTERN OF THE CONTROL MEMSUBJECTED TOTHE ELECTROSTATTIC PATTERN OF THE CONTROL MEMBER, AND SUBSEQUENTLYREMOVING THE CLOTH FROM THE CONTROL MEMBER.